Solo British rower tackles Indian Ocean crossing

A British environmental activist says she hopes her four month journey across the Indian Ocean will raise awareness about the environment.

In what will be her third ocean crossing in six years, Roz Savage has left from Fremantle this morning to row across the Indian Ocean as part of a campaign to raise awareness about ocean pollution.

Ms Savage became the first woman to row solo across the Pacific Ocean when she travelled more than 13,000 kilometres from the United States to Australia, between 2008 and 2009.

She says the trip will take a toll.

"It's mostly a question of holding it together mentally, staying reasonably happy and focused and just keep sticking the oars in the water which sounds pretty straightforward but 12 hours of rowing a day can be a little bit challenging at times," she said.

The 42-year-old will eat freeze-dried meals and nuts and convert salt water to fresh with a miniature desalination plant on the 6,000 kilometre journey.

Ms Savage say she will get through by focusing on the cause.

"I'm trying to get the message out there that we need to take better care of the earth if we're going to have a long-term and healthy future as a species," she said.

"I had my environmental epiphany a few years ago and felt the need to share to bring peoples' attention to this."